JPS623006B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application This invention relates to an air conditioner for automobiles.

b. Prior art The prior art for this type of device is JP-A-57-
There is a publication number 194114. According to the publication, the load sensor detects the engine load by detecting the negative pressure of the intake manifold, and by utilizing the fact that this manifold negative pressure approaches atmospheric pressure during high engine loads, changes in the manifold negative pressure are detected by the diaphragm. The device uses a so-called boost switch that turns the switch on and off based on the movement of the diaphragm.This boost switch turns off the electromagnetic clutch that controls the drive of the refrigeration cycle compressor when the engine is under high load. This reduces the load on the engine.

However, because the negative pressure source for the boost switch as a load sensor is taken in from the intake manifold, the boost switch is constantly turned on and off depending on engine load changes even when the air conditioner is not in use. Not only is the operating sound of the boost switch annoying to the occupants, but the switch also has to be operated many times, which reduces the durability of the contacts.

c. Purpose This invention was made in view of such conventional problems, and provides an air conditioner that improves comfort by eliminating unpleasant operating noise when the air conditioner is not in use, and also improves the durability of the contacts. It provides equipment.

d Configuration In order to achieve the above object, the present invention uses a negative pressure source for a load sensor that detects engine load as a negative pressure source for an air passage of an engine speed control device that increases the engine speed by turning on an operation switch of an air conditioner. This is due to the use of pressure.

e Example In the figure, 1 is an air conditioner unit, and an air passage 2 in this unit 1 is provided with an inside/outside air switching door 4, a blower 6, and an evaporator 8 of a refrigeration cycle R, so that either inside air REC or outside air can be
FRE is introduced into the air passage 2 by a blower 6, passed through an evaporator 8, and turned into cold air, which is then blown out into the vehicle interior from the illustrated blow-off port.

The refrigeration cycle R basically includes a compressor 12 driven by an engine E via an electromagnetic clutch 10, a condenser 14 that condenses the refrigerant (e.g. fluorocarbon gas) compressed by the compressor 12, and this condenser. an expansion valve 18 that expands the refrigerant condensed by the refrigerant 14 after passing through the liquid tank 16; and an evaporator 8 that evaporates the refrigerant exiting the expansion valve 18 and returns it to the compressor 12.
It consists of.

Drive control of the compressor 12 is basically performed by turning on and off the operation switch of the air conditioner, the so-called air conditioner switch 20.
In this example, the compressor is controlled not only by turning on and off the air conditioner switch 20 but also by the compressor controller 22. 12 drive controls are performed in detail. That is, a temperature sensor 24 such as a thermistor is installed near the downstream side of the evaporator 8, and a variable resistor 26 that is linked to a temperature control lever (not shown) and a fixed resistor 28 that switches the reference temperature are connected in series. A switch 30 serving as a load sensor for detecting engine load, which will be described later, is connected in parallel to the fixed resistor 28.

The switch 30 is turned on when the engine E is under low load, and turned off when the engine is under high load. The on/off operation of this switch 30 will be described later. Compressor 1
The drive control described in No. 2 is detailed in Japanese Unexamined Patent Publication No. 194114/1982, so a brief outline thereof will be given here.

When the air conditioner switch 20 is turned on, a signal based on the temperature sensor 24 and the variable resistor 26 is input to the compressor controller 22 when the switch 30 is in the on state, but when the switch 30 is in the off state, the signal based on the temperature sensor 24 and the variable resistor 26 is input to the compressor controller 22. A signal based on the fixed resistor 28 is transmitted to the compressor controller 2.
2 is input. The output of the compressor controller 22 energizes and de-energizes the relay 32 to turn off and on the normally closed contact 32a of the relay 32 to control the energization of the electromagnetic clutch 10 and drive and control the compressor 12. ing.

In this way, the operation switch 30, the temperature sensor 2
4, variable resistor 26, fixed resistor 28, switch 3
0, compressor controller 22, relay 3
2. The electromagnetic clutch 10 constitutes a compressor control circuit.

On the other hand, when the air conditioner switch 20 is turned on, the engine speed control device FICD is activated to increase the engine speed by a predetermined speed (for example, 150 to 250 rpm). That is, the throttle valve 3 in the intake passage 34 of the engine E
A bypass passage 38 is formed before and after the engine 6, a control valve 40 is interposed in this bypass passage 38, and when the air conditioner switch 20 is turned on, the control valve 40 is opened via the engine speed controller 42 and the bypass is activated. This communicates the passage 38 and increases the engine speed.

Vacuum solenoid valve 44 is actuated by turning on air conditioner switch 20 to detect negative pressure downstream of the control valve in bypass passage 38 as a load sensor, and opens the negative pressure passage.
are connected via.

The switch 30 operates a diaphragm 30a based on the difference between the atmospheric pressure Pa and the negative pressure P in the bypass passage 38, and the movement of the diaphragm 30a causes the contact 3 to
As mentioned above, when the engine load is low, the pressure difference between the atmospheric pressure Pa and the bypass passage negative pressure P is large, so the switch is turned on.
When the engine is under high load, it approaches the atmosphere and the diaphragm 30a is activated to switch off. The negative pressure in the bypass passage 38 is used as a negative pressure source for this switch 30, and the negative pressure in the bypass passage is introduced only when the air conditioner switch 20 is turned on, that is, only when the air conditioner is in use. Therefore, the switch 30 is not turned on and off when the air conditioner is not in use, but is turned on and off only when the air conditioner is in use.
It will operate off. As a result, when the air conditioner is not in use, there is no unpleasant operating noise, and the durability of the contacts of the switch 30 is significantly improved.

f. Effects According to the present invention, there is no unpleasant operating noise when the air conditioner is not in use, making driving more comfortable, and the durability of the load sensor contacts is significantly improved, which is a highly practical effect. Demonstrate.

[Brief explanation of the drawing]

The figure is a circuit diagram of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Air conditioner unit, 10...Electromagnetic clutch, 12...Compressor, 20...Operation switch (air conditioner switch), 22...Compressor controller, 30...Engine load sensor, 30a...Diaphragm, 30b...Contact, 34...Intake passage, 3
8...Bypass passage, 42...Engine speed controller.

Claims (1)

[Scope of Claims] 1. A compressor driven by the rotation of the engine is controlled by an operation switch via an electromagnetic clutch, and a load sensor that detects the engine load disengages the clutch to drive the compressor when the engine is under high load. A compressor control circuit that stops the engine, and a bypass passage formed in the engine intake passage.
An air conditioner for an automobile, comprising: a control valve interposed in the bypass passage; and an engine speed control device for opening the control valve by the operating switch to increase engine speed; An air conditioner for an automobile, comprising a switch that operates a diaphragm based on the difference between the negative pressure downstream of the control valve in the bypass passage and atmospheric pressure, and opens and closes by the operation of the diaphragm.